1. Field of the Invention
This invention relates to collagen, and more particularly, to a collagen sponge formed of natural insoluble collagen.
2. Description of the Prior Art
"Natural insoluble collagen" as used herein means and refers to collagen which cannot be dissolved in an aqueous alkaline or in any inorganic salt solution without chemical modification, and includes hides, splits and other mammalian or reptilian coverings. More particularly, "natural insoluble collagen" means and refers to the corium which is the intermediate layer of a bovine hide between the grain and the flesh sides.
In young animals there is little intermolecular and interfibrillar crosslinking which provides for some degree of solubility of the collagen. However, during the aging process both intermolecular and interfibrillar crosslinking occurs, thus making the collagen insoluble.
The use of collagen in substantially pure form has been proposed for many uses, including for burn dressings as disclosed in U.S. Pat. Nos. 3,939,831 and 3,514,518, and similar medical applications as disclosed in U.S. Pat. Nos. 3,157,524 and 3,628,974.
U.S. Pat. No. 3,637,642 is exemplary of a process for dissolving insoluble collagen and regenerating the fiber.
Further methods have been proposed for solubilizing and reconstituting collagen with the use of enzymes to sever intra and interfibrillar bonds, such as is disclosed in U.S. Pat. No. 3,034,852, and other processes have been proposed for converting collagen fibrous masses to sheet-like material, such as in U.S. Pat. Nos. 2,934,447 and 2,934,446.
Further, according to U.S. Pat. Nos. 3,939,831 and 3,742,955, medicinal dressings can be prepared from collagen having dispersed therein antibiotics and the like to aid in the healing of skin which has been burned.
Also, according to U.S. Pat. No. 3,742,955, fibrous collagen has been proposed which has hemostatic and wound binding properties. The collagen is in the form of a fluffy fibrous product which may be converted into nonwoven webs or mats by mechanical techniques.
In accordance with the present invention, a collagen sponge is provided which derives its integrity through chemical bonding of the particulate native collagen. Further, the collagen sponge in accordance with the present invention has wound healing properties and hemostatic properties.